1. Field of the Invention
Embodiments of the invention relate generally to the field of electrically insulating materials, particularly of the dielectric type. Embodiments of the present invention may be applied in particular to electrically insulating materials for high voltage generators, used for example in the medical imaging field.
2. Description of the Related Art
Numerous electrically insulating materials have been developed, particularly to ensure the insulation of high voltage generators, supplying for example, X-ray tubes used in medical imaging.
A known polymer based dielectric material in use today is polypropylene combined with talc. These types of insulators can withstand a very strong electric field. For example, they can be subjected to voltages of the order of 80 kV/cm.
However, above a certain voltage value (known as “start” voltage), partial discharges begin through the material and the polymer degrades irreversibly, as does its insulation properties.
Because the currents dig into the material, certain molecules of the polymer undergo a rearrangement of the polymer molecules, which progressively degrades the insulation capacities thereof, up to its breakdown.
However, increases in power are required to increase the frequency at which this type of device may take images. This requires increasing the voltage delivered by the high voltage generators, while minimizing the weight of the generators because they are typically mounted on the scanner.
In addition, smaller and smaller dimensions are required for high voltage generators, in order to increase the rate at which images may be taken with the imaging devices on which they are mounted. This requires that the voltage delivered by the generators be increased, while minimizing the weight of the generators, because they are mounted on scanners.
Consequently, there exists a need to develop novel electrically insulating materials, capable of withstanding ever stronger electrical fields without overloading the generators on which they are mounted.